a larger one (typically a /8), which assigns subnets from the larger one to IP addresses on the smaller one, and enables automatic and simple tunnelling and routing between systems on the larger address space. Fan addresses are assigned as subnets on a virtual bridge on the host, which are mathematically related to the primary (or underlay) IP address behind which they are mapped. The fan system can be considered “address expansion,” as it simply multiplies the number of available IP addresses on the host, providing an extra 253 usable addresses for each host IP address on the /16.